Visualization components include components or interfaces for applications that allow users, such as software developers, to visualize and display data in meaningful ways. Many visualization components have built-in, interactive regions with which software developers can stylize based on the data. Mapping components are one example of a visualization component that may include existing, built-in regions. However, these visualization components typically do not allow developers to easily group the existing regions into an aggregated region. In the case of mapping components, for instance, developers are not able to group certain states to form a region. For example, developers cannot easily group California, Oregon, and Washington states into a larger region called “West.” Another limitation of existing visualization components is that they typically force users to work with non-visual forms of the territories, such as tables and trees.